PennaGroup, a construction firm in Fort Worth, Texas, is one company vying to build the wall – but it’s not proposing a standard concrete fixture.

The company submitted a design for a wall made of wire and plexiglass that would work similarly to a one-way mirror. The US side would be able to see through the wall, while the Mexico side would not.

According to PennaGroup’s summary of the design, it interviewed dozens of US Border Patrol agents to understand their jobs and what kind of characteristics they would want for a wall. It then designed one that’s tall, can drain rainwater, has mechanized doors for vehicles, and is hard to climb, tunnel under, or tamper with.

PennaGroup did not respond to Business Insider’s request for comment.

While the firm’s design may seem a little bizarre, it’s more serious than other proposals, some of which were intended to mock the premise of a wall.

JM Design Studio, an artist collective based in Pittsburgh, Pennsylvania, submitted six border-wall designs to the US Department of Homeland Security, including one made of tree-strewn hammocks and another made of 10 million pipe organs. And a group of Mexican and American engineers called MADE Collective proposed a $15 billion hyperloop instead of a wall.